Hoist-controller.



No, 872,524. I PATENTED DEC. 3, 1907.

'S. H. LIBBY & I. F. BAKER.

HOIST CONTROLLER.

APPLIOATION FILED MAE. 7, lsqs.

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m ls cu: EBake No. 872,524. PATENTED DEC. 3,1907. 3. H. LIBBY & I; F. BAKER.

HOIST CONTROLLER.

APPLICATION FILED MAB. 7. 1906.

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FB cxkeri novelconstruction and arrangement of parts iinrrn s rens PANT orrron SAMH. LIBBY AND Isaac r. BAKER, or EAST ORANGE, NEW JERSEY, Assrenoas asman ELECTRIC COMPANY, A CORPORATION or NEWJERSEY.

HOIST-CGNTROLLER.

To all whom it may concern:

Be it known that we, SAM H. LIBBY and Isaac F. BAKER, citizens of the United States, residing at East Orange, county of. Essex, State of New Jersey, have invented certain new and useful Improvements in Hoist-Controllers, of which the following is a specification.

The present invention relates to grabbuckct hoist apparatus and has for its object to improve the controlling means for operating ropes so as to render the operation of the hoist convenient and certain. V

In-an application filed by Sam H. Libby, March 7, 1906, Serial No. 304,656, for grabbucket hoist apparatus, there is disclosed a novel system of control for grab-bucket hoists for simplifying and improving the op.

eration of such hoists. In said system the holding rope is maintained taut at all times; but during the lowering of the bucket this is effected by an auxiliary load-brake.

The present invention contemplates a for accom lishing the same purpose without the use p" auxiliary apparatus, the holding motor" itself performing the function of a load-brake during thedescent of the bucket. In this aspect the present invent-ion may be regarded as comprising an improvement on the apparatus disclosed in said application. The above end is attained by so constructing the controller that whenever the holding motor is ,ener ized it is in a direotion tending to wind up the holding rope, and by either making'the holding motor small so that it' will at all times have only sufficient power to maintain the holding rope taut, or else cutting down its power by means of resistance when the bucket is closing and when it is descending under its own weight. Further, the closing and the holding motors are energized simultaneously when it is desired to either close the bucket, raise it or lower it. Thus, when the bucket is being lowered upon the material, both ropes are being paid out, but the holding rope unwinds only so long as the pull of the bucket is greater than that of the holding motor; therefore when the bucket comes to rest upon the'material to be moved, the unwinding of the holding rope Specification of Letters Patent.

Application filed March 7.1906. Serial No. 304,657.

Patented Dec. 3,

immediately ceases and the rope is held taut; while, as soonas the closii motor is set in operation to close the hue et, the holding motor begins to pull upon the holding rope and takes up any slack which might other- 1 1 wise be formed. 1 The present invention will be more fully understood and its objects and 'advant'a es will be more apparent from the following otailed description. In the accompanying drawings we have illustrated a preferred form of the present in vention, Figure 1 showing inside elevation a carrier adapted .to move along an elevated track and provided with the improved hoist-' ing mechanism; Eig. 2 showin an end eleva' tion of the same apparatus; i bei adiagram showing the holding anc the closing. motors, together with the controller and cir-J' euits therefor; and Figs. em 11, inclusive, showing the various motor connections in the several positions of the controller. Referring to Figs. 1 and 2, Arepresents a grab-bucket of the usual clam-shell type suspendedfiom a traveling carriage B, by holding and closing ropes 1 and 2, respec tively; theseropes being Wound upon drums, 3 and 4 operated by electric motors 5 and 6. 7 'is a controller for the motors 5 and6;this controller being located on the operators platform 8.. 9 is a traverse motor whereby the carriage may bemoved along the track; 10 to convey the bucket from one point to' another. Current for the several motors is obtained-from trolley wires 11 and 12 which are engaged by current-collecting devices 13 and. 14, respectively, mounted on the carriage. These .parts, with the exception of the controller, may all take any usual or pro ferred forms, the particular forms shown being simply illustrative of general types of apparatus to which the present invention may beaplied. I

In fig. 3 the controller 7 is shown in de veloped-forni and is illustrated as having eight different positions, including the off position. The controller comprises a series of fixed contact fingers a to a, and two series of movable contact fingers to 0 Assuming that the carriage .has been brought above and the bucket has been b'to b and c 10( circuit, is, however, too weak to lift tne dropped upon the material to be moved, then in order to close the bucket and elevate the load, the controller is moved into its first running position wherein the movable contacts engage with the fixed contacts'along line 11. A circuit may now be traced from trolley wire 11, to contacts a, b, b, a), resistance sections R and R, brake coil 15, armature of motor 6, contacts a, b, a, field of the motor 6, switch E, contacts (1 b 6", a, trolley 12. A branch circuit passes from contacts a and I), through contacts I) and (1,, resistance r, armature and field of motor 5, and thence through switch E back to trolley 12, as before. At a the branch circuit divides anda portion of the current passes through the coil of brake 16 before reaching switch E. The circuit conditions are shown in Fig. 5. The brakes controlled by the coils l5 and 16 are released and both motors tend to wind up their respective cables. The motor 5, with the resistance 'r in bucket and therefore simply maintains the holding rope taut. The motor 6, however, begins to wind up cable 2 and the bucket is closed. -'As soon as the bucket has been completely closed, the controller is moved to its second position and the motor circuits remain unchanged except that resistance sec-- tion R is cut out by reason of contacts a and b coming into engagement. The closing motor now has sulficient power to slowly lift the bucket with its contents, but the holding motor still does little more than keep the holding rope taut. The motor circuits in this position of the controller are indicated in Fig. 6. Upon moving the controllento its third position, resistance section R is cut out and the bucket is lifted more rapidly.

It is clear that the holding motor may either be a small motor of suflicient capacity .only to maintain the holding rope taut, or

it may be made larger so as to assist the closing motor in raising the load, in which latter case the resistance 1" is provided for cutting down the power of this motor when it is operating simply as a holding motor. Therefore, when the controller is movedto its third running position, whereby all external resistance is removed from the circuit of the closing motor, the resistance section 1 is also cut out of the circuit of the holding motor by're ason of theenga ement of contacts a and 12 so that the olding motor may assist the closing motor in raising the load. Fig. 7 'llustrates the circuit-conditions for this position of the controller. When the bucket has reached the proper height, the controller may either be turned to the ofi position or to the fourth running position wherein all the circuits are interrupted, just as in the off position, (see Figs. 4 and 8), and the motors are held stationary through the operations of the brakes controlled by the coils 15 and 16. The carrier may now be operated to convey the bucket to the 'point at which it is to be dumped, and when this point is reached and the controller is turned in the fifth running position, current is supplied to motor 6 as in the first running position, namely, with 'all resistance in circuit, the relative connections of the field and armature being reversed, however, as indicated in Fig. 9. In this position the holding motor 5 remains denergized, since contact 0 is out of engagement with contact a consequently the holding rope is held stationary through the action of the brake controlled by coil 16 and the closing rope is unwound. As soon as the closing rope becomes slack, the bucket of course opens and .drops its contents. The bucket, now being open, may be lowered again upon the material to be moved by turning the controller to the sixth running position, when it willbe seen the circuit of motor 6- will remain unchanged except that the resistance is all removed, but current will be supplied to the motor 5 in the same direction as is the case-when the controller is in the first to thethird -positions. \Nherethe motor 5 is larger than. necessary to simply maintain the holding rope taut, the resistance r is again inserted in the sixth position of the controller so that the empty bucket overhauls the holding motor and descends due to itsown weight.- Nhen the bucket reaches the material,- the controller is returned to its off position, preferably by moving it through the seventh position. The motor circuit-s arev now all interrupted and the holding ro e, which cannot become slack while the holding motor is energized, is held taut through the action of brake 16. The seventh position. of the controller is provided so that the loaded bucket may be lowered before it-is dumped. Thus, after the bucket hasfbeen lifted-by turning the controller through its first three running positions, the controller may be returned to the offlposition and'its motion continued in that direction until the seventh position is reached. 1 In this position of the controller the motor circuits are those indicated in Fig. 11, being exactly the same as those produced in the sixth running position, except that all the resistance is included in the circuit of the closing motor this being for the purpose of preventing the closing motor from running so fast that .its ro e becomes slack and allows the materialto e dumped. After the bucket has been lowered the desired extent it may be dumped as previously described, by turning the controller to the fifth running position.

The switch E is a limit switch arranged to open the motor circuits at the extreme upper limit-of the bucket and comes into operation l l I i by Letters Patent of the United States, is,

l. Ina grab-bucket hoist, a bucket, a holding rope, a closing rope, motors connected to said ropes, and means for causing the motor for the closing rope-to pay out the closing rope to lower the bucket and for causing the motor for the holding rope to place the holding rope under tension in lowering the bucket. i

2. In a grab-bucket hoist, a bucket, a holding rope and a closing rope, motors connected to said ropes, and 1 means for causing said motors tov Wind up said ropes to raise the bucketand for causing the mot-or for the closing rope. to unwind the closing rope and the motor for the holding rope to exert a pull upon the holding rope to lower the bucket.

3. In a grab-bucket h'oist, a bucket, a hold to said ropes, and means for causing the motor for the. closing r0 e to wind up the closing rope in raising the ucket and unwind the closing rope. in lowering the bucket and for causing the motor for the holding rope to exert a u inding effort on the holding rope both in raising and lowering the bucket.

4. In a grab-bucket hoist, a holding rope, a closing rope, motors connected to said ropes, and a controller having contacts and connections arranged to ener ize the motor for the closing rope so as to eit or Wind up or unwind the closing rope and to energize the,

motor for the holding rope only so as to tend to wind up the holding rooe. 45

5. In a grab bucket hoist, a bucket, a holdingrope and a closing rope connected to said bucket, motors connected to said ropes for operating the same, and a controller having contacts and connections arranged toenergize both motors so as to wind up the said ropes to raise the bucket and to energize the motor for the closing rope so as to unwind the closing rope and the motor for the holding rope so as to tend to wind up the holding rope in order to lower the bucket.

.6. In a grab-bucket hoist, a bucket, a hold.- ing rope and a closing rope connected to said bucket, a motor connected to the closing rope, and a motor connected to the holding rope, the said latter motor being adapted to Q exert power suflicient only to maintain the holding rope taut both when the bucket is being closed and when it is being lowered.

7. In a grab-bucket hoist, a bucket, holding rope and a closing rope connected to said bucket, a motor connected to the closing ro e and a motor connected to the holdin rope, the said latter motor being adapted to exert power su'lIic-ient only to maintain the holding rope taut when the bucket is being lowered. W

8. In a grab-bucket hoist, a bucket, aholding rope and a closing rope connected to said bucket, electric motors connected to said ropes for operating the same, each of the said motors being provided with brakes arranged to be released when the motor-circuit is closed, and an electriccontroller for the said motors, the system being so constructed and arranged that both motors will be energized simultaneously and the motor connected to the holding r0 e will exert power sufficient to maintain the olding rope taut both when the bucket is being closed and when it is being lowered.

9. In a grab-bucket hoist, a bucket, a holding and a closing rope, motors connected to said ropes for operating the same, and a controller having contacts and connections arranged to energize both motors simultaneously in a direction to wind up the ropes in mg rope and a closing rope, motors connected order to close the bucketand to energize the motor for the closing rope in a direction to unwind the closing rope and the motor for the holding rope in a direction tending to wind u the holding rope in order to lower the hue et.

10. In a grab-bucket hoist, a bucket, a holding rope and a closing rope connected to said bucket, motors connected to said ropes for operatin the same, and control apparatus arrange to simultaneously energlze the motor connected to the closing rope and supply the motor connected to the holding rope with only suflicient current to maintain t e holding rope taut in order to close the bucket, to incr ttse the current su ply to both motors in order to raise the bucket and to reverse the direction of'rotation of the motor for the closing rope and supply the motor 31- connected to the holding rope with current 111 the same direction sufficient to maintain the holding rope taut in order to lower the bucket.

. 1].. In a grab-bucket hoist, a bucket, a holding rope and a closing rope connected to said bucket, motors for o crating said ropes, resistances, and a controlIer for said motors, said controller having contacts and connections arranged to simultaneously com lete the circuits of said motors throu h sair resistances to cause the motor for t e holding rope to maintain the holding rope tautand themotor .for the closing'rope to close the bucket, and to remove said resistances from the motor circuit in order to cans; both mtors to operate to raise the bucket, said 0011- 1 111 Witness whereof, we have hereunto set troller also having contacts and connections 1 our hands this fifth day of March, 1906. V constructed and arranged to ener ize' the 1 SAM H. LIBBY.

holding motor in a direction to Wind up the E ISAAC F. BAKER. 5 holding rope and the closing motor in a direc- Witnesses: tion to unwind the closing rope in order to l ROGER HJBUTTERWORTH, lower the bucket. ANNA M. GILLIN. 

